Stoker



J. T. ARNOLD.

STOKER. APPLICATION FILED JUNE 5,1917.

1,3?9,672 Patented May 311, 11921.

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i,%'i%?, d 3'%, Specification of Letters Patent Patented May 31, Titian.

Application filed J'une 5,

To aZZ whom it may concern:

Be it known that 1, JOHN T. ARNOLD, a citizen of the United States, and a resident of Attica, in the county of lVyoming and State of New York, have made a new and useful Invention in Stokers, of which the following is a specification.

This invention relates to stokers and has for an object to produce anew and improved means for varying the effectiveness of one or more fuel feeding or fuel impelling rams or plungers.

A further object is to produce a stoker in which an adjustable fender is provided for a ram or plunger so as to vary the effectiveness of the plunger in propelling the fuel through the furnace and in breaking up the fuel bed.

A further object is to produce a Stoker in which a plunger having a constant stroke is employed for moving and agitating fuel but which is provided with an adjustable but normally stationary fender for varying the effectiveness of the plunger in moving or agitating the fuel.

These and other objects are attained by means of the apparatus embodying the features herein described, and illustrated in the drawing accompanying and forming a parthereof.

The drawing is a diagrammatic sectional View of a stoker equipped with my invention.

It is well known to employ not only fuel feeding plungers in underfeed stokers, but to employ auxiliary plungers which operate to propel the fuel across the fuel supporting elements and to break up the fuel bed. It is old to proportion the throw of both the fuel feeding plungers and the auxiliary plungers for the purpose of meeting existing conditions within the furnace. This, so far as I know, has always been accomplished by employing adjustable means, such as lost motion connections, for transmitting power to the auxiliary plungers and, in view of the fact that the auxiliary plungers are ordinarily operatively connected with the main plungers, the operating mechanism is complicated, liable to get out of order, and is more or less expensive to manufacture and assemble. These difliculties and disadvantages are overcome in the apparatus embodying my invention, by providing means for varying the effectiveness of the auxiliary 1917. Serial no. 172,928.

plungers without varying the throw of the plunger, or the ad ustment of the operating connections between the fuel feeding or I mam plungers and the fuel impelling or aux This is accomplished in purpose of varying the fuel feeding efi'ectiveness of the plunger. Referring now to the drawings:

Fuel is fed into the furnace from a hopper 5-by means of a fuel feeding or main plunger 6. In the furnace illustrated, the fuel so fed enters the upper end of a retort 7, which is inclined from the front to the rear of the stoker and is bounded laterally by parallel fuel supporting twyer surfaces 10, extending from the front to the rear of the furnace. It will be understood that the furnace illustrated includes a number of retorts 7 and consequently a number of twyer surfaces 10 formed by twyers 10' adapted to supply air to the fuel bed in a manner well known in this art. For the purpose of aiding the main plunger in moving the fuel downwardly across the fuel supporting elements and for the further purpose of breaking up the fuel bed, each retort is provided with an auxiliary plunger 11, which as shown, is adapted to move into and out of the fuel bed and in this way agitate the fuel bed, break up the clinker, etc, and aid in moving the fuel and ash toward the dump grate 12.

Any suitable means may be employed for reciprocating the plungers, but for simplicity the operating mechanism will preferably be such that each plunger will be reciprocated with an invariable stroke, although the rate of reciprocation may of course be varied. The operating mechanism shown in the drawing comprises a power shaft 8 upon which is mounted a disk 8'. A connecting rod 6' is pivotallyconnected to the main plunger 6 and the disk 8 at a point to produce the desired reciprocation of the plunger 6. The upper end of a lever 9 is pivotally connected to the outer end of the plunger 6, the lower end of said lever being pivotally mounted upon a bracket 9 secured to the frame of the Stoker. A link 11 connects the auxiliary plunger 11 with the lever 9, so as to reciprocate the plungers 6 and 11 in unison. It is to be understood that the specific operating mechanism herein disclosed is merely illustrative, and forms no part of applicants invention, it being readily apparent that other mechanisms for 0 crating the plungers may be employed.

ach plunger 11 is provided with a cloaking fender 13, which, as illustrated, is adapted to cover the upper portion of the plunger and is adjustable to different positions longitudinally of the plunger. Each fender, as shown, is provided with an actuating gear 14, which meshes with a rack 15, formed on the fender, andis movable, by the cooperation of the rack and gear, to different positions along the line of travel of the plunger. It will, of course, be understood that any suitable means may be employed for mounting the fender and for guiding it 1n its movements into and out of the fuel bed.

The effectiveness of each plunger in propelling fuel and in breaking up the fuel bed is dependent on the effectiveness of its forward throw or stroke. As the plunger moves back fuel from above drops into the space vacated by the plunger and the next for ward motion of the plunger displaces this fuel. By varying the position of the fender 13, more or less fuel is permitted to fill the space vacated by the plunger on its backward stroke, consequently the effectiveness of the plunger as a fuel impelling agent is varied. If the fender 13 1s moved to its innermost position, as shown, the fuel impelling effectiveness of the plunger is minimized. If the fender is withdrawn to the outer limit of its movement, the plunger is effective as a fuel impelling ram throughout its entire inward stroke, since the entire space in front of the plunger will be filled with fuel each time the plunger moves outwardly. From this it will be seen that the fuel impelling effectiveness of the auxiliary plungers may be widely varied by varying the positions of the cloaking fenders.

The arrangement above described is particularly advantageous in connection with progressive feed furnaces utilizing dump grates which are periodically opened for the discharge of ash and clinker into the ash pit.'

For such a construction, the opening of its dump grates removes the support of the fuel bed at its lowermost point, at which time the forward feeding of the plungers projects some of the unburned or only partly consumed fuel past the open dump grate into the ash pit. This waste of fuel is avoided in my construction by providing a fender, which may be moved longitudinally to cloak. or decrease the effectiveness of the plunger so that the unburned fuel will not be forced toward the open dump grate during periods of ash discharge. It is readily apparent that, with the actuating mechanism of the fenders illustrated, all the fenders included by mo'unting all the actuating pinions 14 on Y the same shaft 16. It will also be understood that my invention may be employed in connection with the main or fuel feeding plungers.

While I have described and illustrated but one embodiment of my invention, it will be apparent to those skilled in the art that various changes, modifications, additions and omissions may be made in the apparatus described and illustrated without departing from the spirit and scope of the invention as set'forth by the appended claims.

hat I claim is:

1. In a stoker, a retort, a plunger for feeding fuel into the retort, a second plunger for moving and agitating the fuel after it has been fed into the stoker, and an adjustable fender overlying said second plunger for varying the effectiveness of said second plunger.

2. A stoker including fuel inlet and ash discharge means, a constant-stroke fuel feeding and agitating plunger operative in the combustion chamber between the fuel inlet and ash discharge means, and an adjustable fender arranged above and partially surrounding the plunger to vary the extent of fuel feeding and agitating by the plun- 3. In a stoker of the underfeed type, a retort, a fuel impelling plunger operatingin said retort for agitating fuel undergoing combustion and having a constant stroke,

and means for varying the area of the plunger exposed to the fuel for Varying the effectiveness of the plunger.

4;. In a stoker, a retort, a plunger for feeding fuel'into the retort, twyers for delivering air to the fuel, a reciprocable ram movable into and out of the retort for moving the fuel fed by the plunger, a normally-stationary fender for the ram, and means for moving the fender into different positions along the line of travel of the ram to vary the extent of movement of the fuel by the ram.

5. In a stoker, a retort, a fuelfeeding plunger for feeding fuel into the retort, a reciprocable fuel impelling plunger movable into and out of the retort and adjustable means for varying the fuel agitating efiectiveness of the impelling plunger without varying its stroke.

6. In a stoker furnace, a grate adapted to support a fuel bed, a plunger arranged to agitate the fuel bed, and an adjustable stationary cover for the plunger for varying the maximum area of the plunger exposed to the fuel whereby the effectiveness of the plunger is varied.

7 In a stoker, a grate, a retort for fuel extending along the grate, a fuel feeding plunger for feeding fuel into the front end eraera of the retort, a reciprocable fuel impelling plunger movable into and out of the retort at a point along the retort intermediate its ends for agitating and feeding the fuel along the retort, and adjustable means for varying the fuel agitating effectiveness of the impelling plunger without varying its Stroke.

8. In a stoker furnace, a grate adapted to support a fuel bed, a plunger arranged to agitate the fuel bed, and an adjustable statlonary cover for the plunger adapted toshield a portion of the plunger from contact with the fuel for varying the effectiveness of the plunger.

9. In a stoker furnace a retort, a reciprocable fuel moving plunger adapted to agitate fuel in said retort, a fender resting on the plunger and means for controlling the position of the fender whereby the efiectiveness of the plunger may be varied.

10. A stoker including fuel inlet and ash discharge means, a constant stroke fuelfeeding plunger operative in the combustion chamber between the fuel inlet and ash discharge means and a fender adapted to be moved over the plunger to cloak the effectiveness thereof, whereby, when the ash is being discharged through the ash discharge means,- unconsumed fuel will not be projected into the ash pit.

11. In combination with a stoker, a fuel hopper, a retort, a main fuel plunger adapted to feed fuel from the hopper into the retort, ash discharge means at the end of the retort, an auxiliary plunger arranged in the retort between the main plunger and the ash discharge means, a cover overlying said auxiliary plunger and means for moving the cover in the direction of reciprocation of said auxiliary plunger, whereby for any given position of the cover, the effective range of the auxiliary plunger is determined.

12. A stoker including a retort, a fuelan auxiliary fuel pusher in the retort, a

fender overlying the auxiliary fuel pusher and means associated therewith whereby the fender may be moved to render the auxiliary fuel pusher ineffective when ash is being discharged through the ash discharge means.

In testimony whereof, I have hereunto subscribed my name this 31st day of May,

JUHN T. ARNOLD. Witnesses:

C. B. BENEDIUJP,

R. C. Simon, 

